This invention relates to an optical aiming device with means for viewing a target field, means for defining an aiming mark and a partially-reflecting mirror for superimposing the aiming mark on the target field.
Such aiming devices are conventionally used as reflex sights for cannon and other firearms. In his German Offenlegungsschrift No. 2,122,251 William F. Steck of El Paso, Tex. discloses an aiming device with a housing for aiming and a light collecting rod mounted at one side of the housing to serve as an aiming mark. The image of one end surface of the light collecting rod is superimposed on the target field by two mirrors mounted on the housing. There is no means provided to change illumination for various ambient light levels or target luminosities.
Another reflex sight shown in U.S. Pat. No. 2,780,130 by Paul B. Maurer has an aiming mark illuminated by a fluorescent plastic rod which is superimposed on the aiming ray path by a semitransparent concave mirror. A filter with a high transmission for the light of the fluorescent plastic rod may be inserted in the viewing ray path to match very bright targets to the brightness of the aiming mark. An optical aiming device as shown in Swiss Patent No. 576,617 by J. A. I. Ekstrand has a reflex sight where the brightness of an aiming mark is adjustable by an electric lamp or by interchangeable attenuating filters for a betalight illumination.
A reflex sight shown in Swiss Patent No. 318,892 by Karl W. Lange has an illumination for an aiming mark which is adjustable by varying the separation between a beta emitter and a luminous colour. The apparent luminosity of the target may be adjusted by inserting absorbing filters in a revolving disk.
One object of the present invention is to provide an improved optical aiming device with a simple adjustable illumination of the aiming mark with a variable brightness by means of conventional commercially available sources of artificial light of constant brightness.
The invention is directed toward satisfying this and other objects with a device comprising at least one first source of artificial light to illuminate the aiming mark, reflecting means for directing the artificial light to the aiming mark and a partially reflecting mirror whereby the image of the aiming mark can be seen by an observer, viewing the target field, substantially at infinity. At least one of the elements first source of artificial light, aiming mark and reflecting means is movable with respect to the two other elements so that the illumination of the aiming mark or parts thereof varies at the motion.
According to one feature of the invention, the first source of artificial light is self contained, another source of light for illumination of the aiming mark comprises a phosphor that may be activated by daylight and one part of the aiming mark is illuminated by the other source of light comprising the phosphor and another part of the aiming mark is illuminated by the first source of artificial light.
According to another feature of the invention, the aiming mark comprises a central circular spot and several line components arranged radially around said central spot, the reflecting means for directing the artificial light of the first source to the aiming mark is constituted by the lateral area of a truncated hollow cone of which the small aperture is adjacent to the circular spot of the aiming mark and serves to pass the illumination from the other source of light that may be activated by daylight, said lateral area being metallized on its outer side and for each line component of the aiming mark one self contained source of artificial light being provided circularly movable around said truncated hollow cone so that the illumination of the line components via the metallized lateral area varies at a motion of the self contained sources of artificial light.
According to a third feature of the invention, the other source of light which comprises the phosphor has a rod-shaped phosphor which collects ambient light and transmits it directionally from its end surface adjacent to the circular spot of the aiming mark through said small aperture of the lateral area of the truncated hollow cone.
These objects and many other advantages of the present invention will be readily apparent to one skilled in the pertinent art from the following detailed description of a preferred embodiment of the invention and the appended claims when considered in conjunction with the drawings.